It is the 74250. And I was able to figure out how to adjust the pin and lever in the five years I have owned the mower.

The overall height of the deck is my concern. It has, over the years, lost a half an inch of cutting height. Can the threaded bolt be adjusted to raise the deck? Or taking a link out of the chain???

Scotlykins -

Since you reference adjusting the threaded bolt or removing a chain link, there’s a section in the owners manual that dealers with Adjusting the Front-to-Rear Mower Pitch and Leveling the Mower Side-to-Side. Following these procedures typically will resolve issues of Height of Cut. Not sure if you saw this in your owners manual, or if you gave it a try without success? Let us know.

Toro customer care will work with owners of the product, but typically a physical diagnosis is required to resolve most products issues. This isn't something that is easily done over the phone. That is why we commonly refer end users back to their local dealer. Really no different than how the majority of durable goods manufacturers handle service and customer care. Take automobiles for instance, the local dealer is responsible for resolving service issues, not the manufacturer.